Adaptor for hot water storage tank and method of use thereof

ABSTRACT

An adapter allows a hot water storage tank of the kind having an electrical immersion heater fitted into a base of the tank via a flange. The adapter includes a flange having peripheral holes corresponding to holes in the flange of the electrical immersion heater. A cold water outlet mounted project through the flange and allows connection to a cold water inlet of an external heater. A hot water inlet projects through the flange and allows connection to a hot water outlet of the external heater. The hot water inlet is configured so that in use hot water entering therethrough is directed to an uppermost location of the tank.

RELATED APPLICATION

This application is a c-i-p of U.S. Ser. No. 11/820,866 filed Jun. 20,2007 entitled “Water Heating and Storage System” and due to issue asU.S. Pat. No. 7,726,263 on Jun. 1, 2010 the contents of which are whollyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a hot water storage tank that storeswater heated by an external heater.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 7,726,263 discloses a thermosyphonic water heating andstorage system, comprising a heat-insulated main heated water storagetank for storing hot water. As shown in FIG. 1 of this patent, thestorage tank has top, side and bottom walls, a hot water inlet close tothe top wall of the tank for heated water entering the tank, a coldwater inlet, and a consumer hot water outlet. Hot water is heated in anexternal water heater of a capacity up to several liters having top andside walls and a base, and a controlled electrical heating unitprotrudes into an interior of the heater from the top wall thereof. Anoutlet port of the heater is connectable to the inlet of the mainstorage tank and a water inlet port of the heater is connectable to themains water supply.

A first valve is connected between a non-consumer outlet of the storagetank and the water inlet port of the external water heater for allowingprevention of water flow from the storage tank to the external waterheater during maintenance, and a second valve is connected between thehot water inlet of the storage tank and the outlet of the external waterheater for allowing prevention of hot water flow from the storage tankto the external water heater during maintenance. The base of the heateris detachably affixed on to the side walls for easy maintenance of theexternal water heater including maintenance and replacement of theelectrical heating unit.

It emerges from the foregoing and from FIG. 1 of U.S. Pat. No. 7,726,263that the main storage tank requires four ports altogether: a first forentry of cold water and a second for outlet of hot water as are standardfittings in hot water storage tanks However, there are additionallyrequired a third port for coupling to the hot water outlet of theexternal heater and a fourth port for coupling to the cold water inletof the external heater. These additional ports are non-standard thusrequiring that a custom water storage tank be provided in order to enjoythe benefit of the system shown in U.S. Pat. No. 7,726,263.

The need for two additional ports militates against connection of anexternal heater to conventional water storage tanks having only a singleinlet and outlet and, in practice, means that in order to benefit fromthe teachings of U.S. Pat. No. 7,726,263 in an existing water system,the water storage tank must be replaced with a customized tank havingthe requisite four ports. This is wasteful of both material and expense.

There are two different types of hot water storage tank. One usesso-called indirect heating such as shown in U.S. Pat. No. 2,016,746(Ireland) where very hot water is fed from an external boiler through aclosed tube and heats cold water that is circulated through acirculating unit in the tank. The closed tube has connections mounted ina side of the tank for coupling to the boiler. The other type of hotwater tank uses directs heating, whereby an electrical immersion heateris mounted in a base of the tank. It is with such types of tank that thepresent invention is concerned.

FIGS. 1 and 2 of the present application show pictorially in partiallycut-away section a hot water storage tank 10 of the kind manufactured byChromagen of Sha'ar Ha'amakim, Israel. The tank 10 has an outer casing11 in a base 12 of which there are a cold water inlet 13 and a hot wateroutlet 14 that is directed toward the top of the tank where the water ishottest. The tank 10 may be mounted vertically as shown in FIG. 1 whenthere is sufficient headroom, as is common in solar heatingapplications, or it may be mounted horizontally as shown in FIG. 2 whenheadroom is at a premium. In the case where it is mounted vertically,the hot water outlet 14 curves inwardly towards an apex of the storagetank, as shown albeit schematically in the figure. The apex of the tankis not visible in the figure, since the storage tank is covered byinsulating material, only the wall of the lower part of the tank beingshown in partial section.

In the case where the tank is mounted horizontally, the hot water outlet14 is shorter and directed to an upper surface of the tank, the coldwater inlet 13 being taken from the same connection as shown in FIG. 1.In both cases, the hot water outlet 14 is higher than the cold waterinlet 13 and its highest end reaches to where the water in the tank ishottest. For the sake of completeness, it should be noted that hot watertanks are known having three ports in the base: one being the cold waterinlet shown as 13 in FIGS. 1 and 2; the second being a hot water outletthat is disposed toward a center of the base and reaches the apex foruse when the tank is mounted vertically as shown in FIG. 1; and thethird being a hot water outlet that is disposed toward an upper part ofthe base as shown in FIG. 2 when the tank is mounted horizontally. Suchan arrangement allows the same tank to be mounted in either orientation,the unused hot water outlet being sealed.

An electrical immersion heater element 15 having an integral thermostat16 is mounted via a flange 17 in the base 12 of the tank 10. Typicallythe lifetime of such heaters is less than that of the tank and, ifnecessary, the heater can be replaced by removing the flange whereuponthe immersion heater and thermostat are withdrawn and can be replaced.Of course, prior to doing this, water must be drained from the tank andthis, indeed, is one of the drawbacks associated with such tanks, whichis overcome by the arrangement in U.S. Pat. No. 7,726,263.

However, the hot water storage tank as required in U.S. Pat. No.7,726,263 has an additional two ports that are not provided in the tank10 shown in FIGS. 1 and 2. It would therefore be desirable to convert aconventional tank having two ports for use with an external heater ofthe kind taught in U.S. Pat. No. 7,726,263.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to obviate the needto replace the storage tank in a conventional water system whenutilizing an external heater of the kind taught in U.S. Pat. No.7,726,263.

To this end there is provided in accordance with the invention anadapter for converting a hot water storage tank of the kind having anelectrical immersion heater fitted into a base of the tank via a flangeso as to provide a cold water outlet for coupling to an external heaterand a hot water inlet for coupling to the external heater, said adaptercomprising:

-   -   a flange having peripheral holes corresponding to holes in the        flange of the electrical immersion heater,    -   a cold water outlet mounted in said flange so as to project        therethrough and allow connection to a cold water inlet of the        external heater,    -   a hot water inlet mounted in said flange so as to project        therethrough and allow connection to a hot water outlet of the        external heater, said hot water inlet being configured so that        in use hot water entering therethrough is directed to an        uppermost location of the tank.

In accordance with another aspect of the invention, a conventional hotwater storage tank having an electrical immersion heater is adapted foruse with an external heater by:

-   -   removing the electrical immersion heater from the base of the        tank; and    -   mounting the adapter in the base of the tank instead of the        heater while ensuring that the hot water inlet of the adapter is        directed to an uppermost location of the tank.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carriedout in practice, an embodiment will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIGS. 1 and 2 are pictorial representations showing partially cut-awayviews of a known hot water storage tank mounted respectively verticallyand horizontally and being suitable for use with the present invention;

FIG. 3 is a pictorial representation of an adapter according to thepresent invention; and

FIG. 4 is a schematic representation of a modified hot water storagetank coupled to an external heater via the adapter shown in FIG. 3.

In the drawings, identical components that appear in more than onefigure or that share similar functionality are referenced by identicalreference symbols.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 3 shows an adapter 20 for converting a hot water storage tank ofthe kind having a cold water inlet and a hot water outlet and anelectrical immersion heater fitted into a base of the tank via a flangefor use with an external heater as taught by U.S. Pat. No. 7,726,263.The adapter 20 comprises a flange 21 having peripheral holes 22corresponding to holes in the flange of the electrical immersion heater.A cold water outlet 23 is mounted in the flange 21 so as to projecttherethrough and allow connection to a cold water inlet 31 of anexternal heater 30 shown in FIG. 4.

A hot water inlet 24 is mounted in the flange 21 so as to projecttherethrough and allow connection to a hot water outlet 32 of theexternal heater 30. The hot water inlet 24 is configured such that itprojects into the tank via a tube 25 and reaches toward the highestpoint of the tank where the water is hottest. This is important in orderto prevent the hot water entering the storage tank from mixing with coldwater in the storage tank and thereby cooling. Thus, in the case wherethe adapter 20 is intended for use in a vertical tank as shown in FIG.1, the tube 25 is elongated relative to the cold water outlet so that afar end 26 of the tube remote from the flange reaches the top of thetank 10. On the other hand, if the adapter 20 is intended for use in ahorizontal tank as shown in FIG. 2, the tube 25 need not be elongatedbut should be curved toward the far end 26 so that in use the far end 26curves upwardly toward the highest point of the tank. Alternatively, auniversal adapter may employ an elongated tube 25 that is curved towarda free end 26 thereof so as to be suitable regardless of whether the hotwater storage tank is mounted horizontally or vertically.

FIG. 4 shows schematically and not to scale a modified hot water storagetank 11 coupled to an external heater 30 via the adapter 20 in athermosyphonic water heating and storage system. Double arrowheadsdepict the connection of the cold water outlet 23 of the adapter 20 tothe cold water inlet 31 of the external heater 30 and of the hot waterinlet 24 of the adapter 20 to the hot water outlet 32 of the externalheater 30. Water flow between the external heater 30 and the storagetank 11 is thermosyphonic such that hot water entering the storage tankvia the hot water inlet 24 displaces cold water in the tank which flowsfrom the cold water outlet 23 to the cold water inlet of 31 the heater30. The cold water entering the cold water inlet 31 is heated and rises,so that the hot water reaches the hot water outlet 32 and flows into thestorage tank via convection.

The invention also contemplates retrofitting a conventional hot waterstorage tank of the type shown in FIGS. 1 and 2 with the adapter 20 suchthat the tank may be modified after manufacture and sold integral withthe adapter in place of an electrical immersion heater. This is done byreplacing the electrical immersion heater with the adapter 20 with theend 26 of the hot water inlet 24 directed to where the water in the tankis hottest. Typically, this requires removal of the immersion heaterfrom the base of the tank by removing the securing screws; and thenmounting in the base of the tank instead of the heater the flange of theadapter whose peripheral holes correspond to those in the flange of theelectrical immersion heater.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrated embodiments and maybe embodied in other forms without departing from the essentialattributes thereof. The present embodiments are therefore to beconsidered in all respects as illustrative and not restrictive, thescope of the invention being indicated only by the appended claims andequivalents thereof.

1. An adapter for converting a hot water storage tank having anelectrical immersion heater fitted into a base of the tank via a firstflange so as to provide a cold water outlet for coupling to an externalheater and a hot water inlet for coupling to the external heater, saidadapter comprising: A second flange having peripheral holescorresponding to holes in the first flange of the electrical immersionheater, a cold water outlet mounted in said second flange so as toproject therethrough and allow connection to a cold water inlet of theexternal heater, and a hot water inlet mounted in said second flange soas to project therethrough and allow connection to a hot water outlet ofthe external heater, said hot water inlet being configured so that inuse hot water entering therethrough is directed to an uppermost locationof the tank.
 2. The adapter according to claim 1, wherein the hot waterinlet comprises an elongated tube that is configured to reach toward theuppermost location of a vertically-mounted tank.
 3. The adapteraccording to claim 1, wherein the hot water inlet comprises a tube thatis curved toward an end thereof inside the tank so that, when used in ahorizontally-mounted tank, said end curves upwardly toward the uppermostlocation of the tank.
 4. The adapter according to claim 1, wherein thehot water inlet is configured to reach toward the uppermost location ofthe tank regardless of whether the hot water storage tank is mountedvertically or horizontally.
 5. The adapter according to claim 4, whereinthe hot water inlet comprises an elongated tube that is curved toward afree end thereof.
 6. The adapter according to claim 1, being integrallyfitted to a hot water storage tank in place of an electrical immersionheater.
 7. A method for adapting a hot water storage tank having anelectrical immersion heater fitted into a base of the tank via a firstflange for use with an external heater, said method comprising: removingsaid electrical immersion heater from the base of the tank; and mountingan adaptor in the base of tank instead of the heater, comprising:providing a second flange having peripheral holes corresponding to holesin the first flange of the electrical immersion heater, mounting a coldwater outlet in said second flange so as to project therethrough andallow connection to a cold water inlet of the external heater, andmounting a hot water inlet in said second flange so as to projecttherethrough and allow connection to a hot water outlet of the externalheater, said hot water inlet being configured so that in use hot waterentering therethrough is directed to an uppermost location of the tank.